Low-Temperature Bonding for Silicon-Based Micro-Optical Systems

Abstract

Abstract:Silicon-based integrated systems are actively pursued for sensing and imaging applications. A major challenge to realize highly sensitive systems is the integration of electronic, optical, mechanical and fluidic, all on a common platform. Further, the interface quality between the tiny optoelectronic structures and the substrate for alignment and coupling of the signals significantly impacts the system's performance. These systems also have to be low-cost, densely integrated and compatible with current and future mainstream technologies for electronic-photonic integration. To address these issues, proper selection of the fabrication, integration and assembly technologies is needed. In this paper, wafer level bonding with advanced features such as surface activation and passive alignment for vertical electrical interconnections are identified as candidate technologies to integrate different electronics, optical and photonic components. Surface activated bonding, superior to other assembly methods, enables low-temperature nanoscaled component integration with high alignment accuracy, low electrical loss and high transparency of the interface. These features are preferred for the hybrid integration of silicon-based micro-opto-electronic systems. In future, new materials and assembly technologies may emerge to enhance the performance of these micro systems and reduce their cost. The article is a detailed review of bonding techniques for electronic, optical and photonic components in silicon-based systems.

Micro‐Patterning Wettability in Very Large Scale Microfluidic Integrated Chips for Double Emulsion Generation

“…The drop in temperature lowers the ionic mobility in silicon and glass, and thus to maintain the bonding quality we compensate by applying a high voltage, ensuring sufficient ion displacement during the process. [ 34 ] After dicing the Si/glass chip into dies (small chips), each die containing one double emulsion generating device with 50 parallel generators, the dies are loaded in a custom machined metal fitting that contains fluidic inlets/outlet connections (Figure S2, Supporting Information).…”

Ultra-low temperature anodic bonding of silicon and borosilicate glass

“…Graphite susceptors were used to obtain a 1 kW 400 kHz power supply (simultaneously as the high-voltage electrodes of anodic bonding) that conducts heat to the bonding pair and permanently joins the pair in 5 min creating a bonding strength of above 5.0 MPa. Qin et al [13] presented surface activated low temperature (below 450 °C) bonding to be applied for imaging sensors and medical applications. Woetzel at al [14] presented hermetic sealing with use of room-temperature anodic bonding.…”

Low Temperature Cu–Cu Bonding Technology in Three-Dimensional Integration: An Extensive Review

“…The requirements and constraints of the both the technologies ought to be understood thoroughly before applying the proposed methodology for achieving vertical integration. In addition, a good alignment approach is important to achieve fine pitch Cu-Cu bonding [61]. Recently, for example, Sony has successfully fabricated a CMOS image sensor using Cu-Cu bonding technology [62].…”